The NorStent trial was presented this week at the European Society
of Cardiology congress(1). The
trial revisits an old issue comparing long-term outcomes between patients
treated with contemporary drug-eluting stents (DES) and those treated with
contemporary bare metal stents (BMS)(2). The
rationale for the development of DES was the high rate of in-stent restenosis
and target lesion revascularization associated with early bare metal stents(3). DES have become the stent of choice, recommended in guidelines for
almost all indications(4). The
NorStent trial set out to establish whether contemporary BMS, with better design
and different metal composition perform as well as DES in long term follow-up.

The study protocol randomized patients to receive either BMS or DES
in a 1:1. The specific stent was not specified in the protocol and was at the
discretion of the operator. The study was not blinded but all patients received
dual-antiplatelet therapy (aspirin and clopidogrel) for a minimum of nine moths
after stent insertion. The follow-up was performed using registry data, and a
posted quality of life questionnaire. The primary endpoint was a composite of
death and non-fatal myocardial infarction. Important secondary endpoints
included overall revascularization rate, definite stent thrombosis and target
lesion revascularization rate.

In total 9013 patients were randomized in the study over a 29 month
period. At a median follow-up of 5 years there was no difference in the primary
endpoint, nor in other endpoints such as death, myocardial infarction or unstable
angina. There was a significant reduction in target lesion revascularization from
10.3% to 5.3% with DES (p<0.001), with overall revascularization also
reduced from 19.8 to 16.5 (p<0.001). Rates of definite stent thrombosis were
reduced by 0.4% with borderline significance (p=0.05). No difference in
bleeding risk was seen. There was no impact on the quality of life scores.

The results of this study appear surprising at first glance. As a
specialty, we take for granted the benefit of a DES over a BMS. The reduction
in revascularization with DES is small and with no impact on mortality or
quality of life. It should be noted that this study was extremely well run. It
was carried out without industry sponsorship and in a pragmatic fashion. It
approximates real-word care but nonetheless it was well powered – the largest
individual stent study ever carried out. Endpoint assessment was carried out
blinded to the treatment allocation.

The benefit of DES have often been overstated, or perhaps the danger
of BMS. The purpose of DES was to overcome in-stent restenosis, not to reduce
rates of death or myocardial infarction. Atherosclerosis is a systemic disease
and therefore risk factor control, anti-platelet therapy and lifestyle changes
are the important steps in reducing these endpoints. The DES reduced in-stent
restenosis, as expected, very effectively. The other residual fear – that DES
were associated with a higher rate of long-term stent thrombosis can also be
put to bed. However, the results of this trial provide confidence when
delivering contemporary BMS if the indication dictates. There is no need to
fear that the patient is receiving an inferior product, or that this choice
will negatively impact on prognosis.